<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        body{
            background: #f5f5f5;
            margin: 0;
            padding: 0;
        }
        .div1{
            width: 100%;
            height: 30px;
            background: silver;
        }
        .div2{
            width: 100%;
            height: 160px;
            background: white;
            border-bottom: 1px solid silver;
        }
        .div3{
            width: 1200px;
            height: 450px;
            background: white;
            margin:  5px auto;
        }
        .div4{
            width: 1200px;
            height: 120px;
            background: white;
            margin:  5px auto;
        }
        .div5{
            width: 1200px;
            height: 2000px;
            background: white;
            margin:  5px auto;
        }
        .div3-son1{
            width: 200px;
            height: 450px;
            background: red;
            float: left;
        }
        .div3-son2{
            width: 600px;
            height: 450px;
            background: #fffaf5;
            float: left;
        }
        .div3-son3{
            width: 200px;
            height: 450px;
            background: #6061ff;
            float: left;
        }
        .div3-son4{
            width: 200px;
            height: 450px;
            background: #a5ff72;
            float: left;
        }
    </style>
</head>
<body>

    <div class="div1">
        div1
    </div>
    <div class="div2">
        div2
    </div>
    <div class="div3">
       <div class="div3-son1">
           son1
       </div>
        <div class="div3-son2">
            son2---
        </div>
        <div class="div3-son3">
            son3
        </div>
        <div class="div3-son4">
            son4
        </div>
    </div>
    <div class="div4">div4</div>
    <div class="div5">div5</div>

</body>
</html>
